Alkoxymethylisocyanates are known, in particular methoxymethylisocyanate (MMI). These compounds are interesting intermediate products for the production of lacquer binders which are capable of being cross-linked (see e.g. German Pat. Nos. 1,244,410; 1,619,238; 1,911,180 and 1,644,801 and German Offenlegungsschrift Nos. 1,570,578; 1,595,701 and 1,644,815).
In spite of the excellent lacquer technical properties of the binders described in the above literature, alkoxymethylisocyanate derivatives have not so far become established in practice because no technically completely satisfactory method has yet been disclosed for producing alkoxymethylisocyanates. The known method of producing alkoxymethylisocyanates, in particular methoxymethylisocyanate (see e.g. German Auslegeschrift No. 1,205,087) by the reaction of alkyl-chloromethyl ethers, in particular chloromethyl-methyl ethers with sodium cyanate, has the disadvantage that the chloromethyl ether used as starting material is a substance which, manufactured on a large technical scale, is invariably contaminated with physiologically very harmful substances (bis-(chloromethyl)-ether), with the result that the known method of producing alkoxymethylisocyanates, in particular methoxymethylisocyanate, cannot be employed on a large technical scale.
It was therefore an object of the present invention to provide a new process for the preparation of alkoxymethylisocyanates, in particular of methoxymethylisocyanate, which may also be carried out on a large technical scale. The problem may be solved by the process according to the present invention which is described below.